RIVER WEST — With construction already underway in the background, Mayor Rahm Emanuel took part in a groundbreaking ceremony for the Wolf Point West Tower Friday.

Mayor Rahm Emanuel trumpeted it as part of a building boom in the city, with 25 construction cranes soon to be in action across Downtown producing about 1,000 construction jobs a crane.

"This is an exciting day," he said, "with more people going to work in Chicago, the city that works."

Emanuel said Chicago's business district was growing faster than any other city in the nation, and that economic impact would be felt citywide in every neighborhood.

Chris Kennedy, of Wolf Point Owners, said the entire project reflected a $1 billion commitment to the city that goes back to his grandfather Joseph Kennedy and their stewardship of the Merchandise Mart. He said it reflected a Downtown residential as well as a business boom, with 50,000 new residents settling in the city's center.

"We like investing here," Kennedy said. "Every time we attract a new resident to our Downtown, we make a contribution to strengthen the social fabric of Chicago."

Ald. Brendan Reilly (42nd) acknowledged conflicts between existing Downtown residents and new projects, such as River Point across from Wolf Point.

"The Central business district is booming," he said, but added the key to both business and residential growth was adding amenities to make it a neighborhood.

The project is backed by the AFL-CIO Building Investment Trust, and union leaders played a prominent role in the ceremony. Mike Stotz, president of the AFL-CIO Investment Corp., said it would create 3,500 construction jobs overall and hundreds of more permanent jobs when the buildings are completed.

The Wolf Point development consists of "West Tower," "South Tower" and "East Tower," which will be built in three phases, as well as over 400 feet of publicly accessible river walk. It's expected to open for occupancy in the fall of 2015.

Friday's ceremony took place without any protest, but that didn't mean construction hadn't faced some opposition.

The all-residential West Tower, which will be built first, will contain 509 luxury rental units and not exceed 525 feet or contain more than 200 parking stalls, according to the compromise struck between Reilly, River North residents and the development team.

The 950-foot South Tower is a mixed-use space allotted 885 parking stalls.

The East Tower, also a mixed use space at 750 feet, can house any combination of office space, retail space, residential units and hotel space and has 200 parking stalls. It's the last to pop up.

Each construction phase will be preceded by new traffic and impact assessments.

The property, perched right at the Y-shaped intersection of the Chicago River's North, South and East branches, includes more than 100,000 square feet of largely undeveloped space that was once the centerpiece of the city's trade routes.

The Wolf Point development was heavily debated in the 14 months that the proposal has bounced between community meetings and City Hall, with area residents delivering a petition at the final zoning vote arguing that the tower would increase traffic and limit skyline views for adjacent residences.

"It's been a lengthy process that really worked," Reilly said. "I'm sad that not everyone is thrilled with the project, but I think [that] a year from where we started ... this is a vast, vast improvement to what was proposed initially."

The initial proposal called for 1,800 hotel rooms, which Hines Interests, the project's developer, called place-holders "to allow for future changes in market conditions."